This invention relates generally to modular electrical plugs and, more particularly, to a modular plug having performance properties which will be in compliance with Category 6 standards.
The present invention also relates to plug-cable assemblies of a multi-conductor cable and a plug at one end terminating the cable and a plug or other electrical connector terminating the other end of the cable, or the other end being unterminated.
The present invention also relates to a load bar and a terminal blade for a modular electrical plug.
In view of the continual desire to increase the transmission rate of data through electrical cables, new performance standards are being promulgated for modular electrical connectors. Connectors having characteristics in compliance with this standard will be known as Category 6 connectors, or Cat 6 connectors for short.
Although existing modular connectors such as jacks and plugs, e.g., those having characteristics in compliance with the immediate lower standards (Category 5), might be found to be in compliance with Category 6 standards as well, it is advantageous to develop new modular connectors designed specifically to comply with Cat 6 standards.
Cat 6 modular jacks and plugs are intended to be used in data communication networks to enable the flow of information at higher transmission rates than currently available with known modular connectors, including Cat 3 and Cat 5 connectors. However, data transmitted at high rates in multi-pair data communication cables has an increased susceptibility to crosstalk, which often adversely affects the processing and integrity of the transmitted data. Crosstalk occurs when signal energy xe2x80x9ccrossesxe2x80x9d from one signal pair to another. The point at which the signal crosses or couples from one set of conductors to another may be 1) within the connector or internal circuitry of the transmitting station, referred to as xe2x80x9cnear-endxe2x80x9d crosstalk, 2) within the connector or internal circuitry of the receiving station, referred to as xe2x80x9cfar-end crosstalkxe2x80x9d, or 3) within the interconnecting cable.
Near-end crosstalk (xe2x80x9cNEXTxe2x80x9d) is especially troublesome in the case of telecommunication connectors of the type specified in sub-part F of FCC pan 68.500, commonly referred to as modular connectors. The EIA/TIA (Electronic/Telecommunication Industry Association) of ANSI has promulgated electrical specifications for near-end crosstalk isolation in network connectors to ensure that the connectors themselves do not compromise the overall performance of the unshielded twisted pair (UTP) interconnect hardware typically used in LAN systems. It is expected that electrical specifications for Cat 6 plugs will also be promulgated in the near future.
In the prior art, reference is made to the assignee""s U.S. Pat. No. 5,628,647 (Rohrbaugh et al., incorporated by reference herein) which describes Cat 5 modular plugs including a management bar or load bar for receiving the conductors in separate conductor-receiving passages or channels. Inter-conductor capacitance in the plugs is reduced by offsetting adjacent conductors, i.e., vertically spacing adjacent conductors from one another, such that the conductor-receiving channels, and thus the conductors, are arranged in two planar arrays spaced one above the other. The offset conductors help to lower the plug""s internal capacitance thus enabling compliance with, for the disclosed plugs, Cat 5 standards.
It is an object of the present invention to provide new and improved modular plugs and modular plug-cable assemblies including the same.
It is another object of the present invention to provide new and improved modular plugs and modular plug-cable assemblies including the same in compliance with Category 6 standards.
It is yet another object of the present invention to provide new and improved designs of modular plugs offering crosstalk performance better than that of existing modular plugs.
It is still another object of the present invention to provide a new and improved conductor management bar or load bar for use in modular electrical plugs.
It is another object of the present invention to provide new and improved terminal blades for use in modular electrical plugs.
Briefly, in accordance with the present invention, these and other objects are achieved by providing a modular plug including a plug housing made of dielectric material including a plurality of parallel, spaced, longitudinally extending terminal-receiving slots at a forward end and a longitudinal cavity extending from a rear face thereof forward to a location below the slots such that the cavity is in communication with the slots. Each terminal-receiving slot receives a respective terminal blade or insulation displacing contact. The plug also includes a conductor management bar, or load bar, arranged in the cavity and defining conductor-receiving channels in which the two channels receivable of the conductors forming conductor pair #3, i.e., conductors 3 and 6 according to TIA/EIA-ANSI standard 568B, are located in a first row or level while the two channels receivable of the conductors forming conductor pair #1, i.e., conductors 4 and 5 according that standard, are located in a second row or level substantially parallel to and spaced from the first level. Preferably, the channels receivable of conductors 4 and 5 are spaced laterally inwardly, i.e., between the channels receivable of conductors 3 and 6.
In a first preferred embodiment comprising an 8-position plug (terminating four twisted wire pairs), the conductor-receiving channels are located in three substantially parallel rows or levels arranged such that each level receives at least one pair of conductors operatively forming a circuit during use. The channels adapted to receive the conductors forming conductor pair #1, conductors 4 and 5, and the channels adapted to receive the conductors forming conductor pair #3, conductors 3 and 6, are situated in the levels most distant from one another to thereby reduce crosstalk between these conductor pairs. The two additional pairs of channels are situated at a third intermediate level between the first and second levels.
More particularly, according to a first embodiment of the invention, the load bar housing includes first (or rearward), second (or intermediate) and third (or forward) longitudinally adjoining portions, the third portion being situated below the contact-receiving slots and each portion having a different transverse cross-sectional form, although the load bar housing is a unitary member. At one (a top) level, two channels are formed from, a longitudinal indentation or trough on an upper surface of the first (or rearward) portion, a shaped cavity or bore in the second or intermediate portion and a longitudinal indentation or trough on an upper surface of the third portion). A groove is provided in the first and second portions to receive a conductive strip and hold the conductive strip between the channels in the first level and thereby correct an impedance problem arising from the horizontal separation of the conductors received in the channels in this level. At a second (a bottom) level, two channels are formed from a respective longitudinal indentation on a lower surface of the first portion, a shaped cavity in the second portion and a respective indentation on an upper surface of the third portion. At a third (an intermediate) level, two additional pairs of channels are formed within the load bar housing and between the first and second levels. The load bar assembly preferably comprises means for distributing crosstalk between the pairs of conductors received in the channels in the third level and the pairs of conductors received in other channels and operatively forming a circuit during use, i.e., conductive strips situated alongside the channels.
The conductive strips may be strips of metallic material such as copper, strips of conductive plastic, strips of insert molded plastic surrounding a metal strip or an electroplated strip of plastic, i.e., plastic overlaid with metal.
A second embodiment of the invention comprises an 8-position plug that does not require three separate levels of conductor-receiving channels in the plug housing. According to the second embodiment, the load bar assembly includes a load bar housing defining a plurality of longitudinally-extending conductor-receiving channels for receiving conductors of the cable in which, like the case of the first embodiment, the two channels receivable of the conductors designated 3 and 6 forming conductor prior #3 are located in a first top row or level while the two channels receivable of the conductors 4 and 5 forming conductor pair #1 are located in a second or bottom row or level substantially parallel to and spaced from, and are between the channels in, the first level and between the channels in the first level. The second embodiment differs from the first embodiment in that two additional pairs of channels receivable of the other conductors forming the other two conductor pairs are situated in the same level as that in which the channels receivable of conductors 4 and 5 forming conductor pair #1 are located, i.e., the bottom level. The load bar housing of this embodiment also includes three longitudinally adjoining portions, and the channels are formed in the load bar housing by an arrangement of indentations or troughs and shaped cavities or bores similar, but not identical to the arrangement in the first embodiment. An elongate conductive strip arranged between two channels receiving two conductors operatively forming a circuit during use. The load bar housing preferably also includes a groove parallel to and between these two channels in which the conductive strip is arranged.
In another embodiment of the plug in accordance with the invention which does not require three separate levels of conductor-receiving channels in the plug housing (although it is a preferred construction), the plug includes a housing defining a plurality of terminal-receiving slots and a longitudinal cavity extending from a rear surface of the housing, terminal blades arranged in the slots and a load bar assembly including a load bar housing defining a plurality of conductor-receiving channels for receiving the conductors of the cable and guiding the conductors to a location below the slots such that the terminal blades are displaceable to penetrate the conductors when the conductors are received in the channels. Further, the load bar assembly includes means for distributing, within the pair of conductors received in one pair of channels and operatively forming a circuit during use, crosstalk generated between that pair of conductors and pairs of conductors received in other channels. The longitudinal cavity may extend from the rear surface of the housing to a location below the slots and be in communication with the slots whereby the load bar assembly would extend in the cavity to a location below the slots.
The modular plug-cable assembly in accordance with the invention includes a multi-conductor cable and at least one plug as described above terminating a respective end of the cable. The other end of the cable may be terminated by a plug as described above or another electrical connector, or left unterminated. In the latter case, the purchaser of the plug-cable assembly could terminate the unterminated end as desired.
A load bar for a modular plug in accordance with the invention includes a unitary housing defining a plurality of channels arranged in at least two substantially parallel levels whereby each level includes at least two channels. The housing is elongate and includes first, second and an optional third longitudinally adjoining portions each having a different cross-sectional form. In a first three-level 8-position embodiment, each of two channels for receiving conductors 3 and 6 of conductor pair #3 are defined by a longitudinal indentation on an upper surface of the first portion, a cavity in the second portion and an indentation on an upper surface of the third portion and these channels constitute a first level of channels. The housing also preferably includes retaining means for retaining at least one conductive strip, e.g., a groove arranged between the channels in the first portion and the cavities in the second portion. Two additional channels for receiving conductors 4 and 5 of conductor pair #1 are defined by a respective longitudinal indentation on a lower surface of the first portion, a cavity in the second portion and a respective indentation on an upper surface of the third portion and constitute a second level of channels. These channels are preferably arranged between the channels in the first level in a transverse direction of the housing. Further, for the third level, two additional pairs of channels are situated at a common level between the first and second levels of channels. The housing preferably includes means for retaining at least one conductive strip between the channels for conductors forming a circuit pair, such as two pair of longitudinally-extending grooves formed in the first and second portions alongside the channels in the third level.
In a second two-level 8-position embodiment of the load bar, each of two channels for conductors 3 and 6 of pair #3 are defined at a first or upper level by a longitudinal indentation or trough extending on an upper surface of a first portion and extending partially into the second portion, a shaped cavity or bore extending through the remainder of the second portion and an indentation or trough extending on the upper surface of the third portion. Similar conductive strip retaining means are provided for retaining a conductive strip between the two channels in the upper level. Each of two additional channels for receiving conductors 4 and 5 of conductor pair #1 are defined at a second or bottom level by a shaped cavity or bore extending through the first and second housing portions and an aligned indentation or trough extending on the upper surface of the third portion. These channels are preferably arranged between the channels in the first level in a transverse direction of the housing. Further, two additional pairs of channels for the conductors of pairs #2 and #4 are situated in the second or bottom level. These channels are also formed by shaped cavities or bores extending through the first and second housing portions and aligned indentations or troughs extending on the upper surface of the third portion.
A terminal blade for a modular plug in accordance with the invention comprises a flat conductive member having a first portion having an upper edge surface adapted to contact a contact of a mating electrical connector, a second portion adjoining the first portion and having a narrow length than the first portion and a third portion adjoining the second portion and having insulation-piercing tines. A notch is defined in the upper surface to partition the upper surface into two sections, each defining a side of the notch.